Turn on the fixed position stacking context flag by default

content/public/common/content_switches.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Defines all the "content" command-line switches.
 
 #ifndef CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_
 
 #include "build/build_config.h"
@@ skipping 176 matching lines @@
 extern const char kWebWorkerProcessPerCore[];
 extern const char kWebWorkerShareProcesses[];
 CONTENT_EXPORT extern const char kWorkerProcess[];
 CONTENT_EXPORT extern const char kZygoteCmdPrefix[];
 CONTENT_EXPORT extern const char kZygoteProcess[];
 CONTENT_EXPORT extern const char kDisableSoftwareRasterizer[];
 extern const char kDefaultTileWidth[];
 extern const char kDefaultTileHeight[];
 extern const char kMaxUntiledLayerWidth[];
 extern const char kMaxUntiledLayerHeight[];
-CONTENT_EXPORT extern const char kFixedPositionCreatesStackingContext[];
+CONTENT_EXPORT extern const char kEnableFixedPositionCreatesStackingContext[];
+CONTENT_EXPORT extern const char kDisableFixedPositionCreatesStackingContext[];
 
 extern const char kEnableVisualWordMovement[];
 
 #if defined(OS_ANDROID)
 extern const char kUseMobileUserAgent[];
 #endif
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 extern const char kScrollPixels[];
 #endif
 
 #if defined(OS_MACOSX) || defined(OS_WIN)
 extern const char kUseSystemSSL[];
 #endif
 
 extern const char kEnablePerTilePainting[];
 
 #if defined(USE_AURA)
 CONTENT_EXPORT extern const char kFlingTapSuppressMaxDown[];
 CONTENT_EXPORT extern const char kFlingTapSuppressMaxGap[];
 CONTENT_EXPORT extern const char kTestCompositor[];
 #endif
 
 }  // namespace switches
 
 #endif  // CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_